Sets the GdbusModem3gppUssd instance for the D-Bus interface <link linkend="gdbus-interface-org-freedesktop-ModemManager1-Modem-Modem3gpp-Ussd.
top_of_page">org.freedesktop.ModemManager1.Modem.Modem3gpp.Ussd</link> on this.
| this | |
| interface_ |
A GdbusModem3gppUssd or null to clear the interface. |